1. Field of the Invention
The invention relates to a device. More particularly, the invention relates to an organic electroluminescence device and a method of manufacturing the same.
2. Description of Related Art
An organic electroluminescence device is an optoelectronic device capable of efficiently converting electric energy into light, and the organic electroluminescence device often serves as an illumination source, a display panel, and so forth. Since the organic electroluminescence device is characterized by wide viewing angle, simple fabrication, low costs, high response speed, wide operating temperature range, and full-color display, the organic electroluminescence device satisfying the requirement for the multi-media display has become a popular research topic in recent years.
FIG. 1 is a schematic view illustrating a conventional organic electroluminescence device. With reference to FIG. 1, the organic electroluminescence device 100 includes a substrate 110, a first electrode 120, a hole injection layer 130, a hole transporting layer 140, an organic light-emitting layer 150, an electron transporting layer 160, an electron injection layer 170, and a second electrode 180. In general, the first electrode 120, the hole injection layer 130, the hole transporting layer 140, the organic light-emitting layer 150, the electron transporting layer 160, the electron injection layer 170, and the second electrode 180 are sequentially stacked onto the substrate 110. Besides, the second electrode 180 is made of metallic materials with excellent reflectivity, such that light emitted from the organic light-emitting layer 150 is reflected for the purpose of display.
The second electrode 180, in most cases, is a flat electrode layer that can provide a reflection function. Moreover, the air, the substrate 110, the first electrode 120, the hole injection layer 130, the hole transporting layer 140, the organic light-emitting layer 150, the electron transporting layer 160, and the electron injection layer 170 have different refractive indexes, such that the light whose incident angle is greater than critical angle leads to total reflection among interfaces of different layers. Owing to the reflection of the second electrode 180 and the total reflection among the interfaces, the light emitted from the organic light-emitting layer 150 and having the incident angle greater than critical angle will be trapped in between substrate 110 and the second electrode 180. Under said design, approximately 20% of the light emitted from the organic light-emitting layer 150 can pass through the substrate 110, thus resulting in a low external efficiency of the organic electroluminescence device 100.